What should I ask a supplier's reference?

Ask about a specific past problem and how it was handled, not whether the supplier is generally good. A general question invites a general, unhelpful answer.

How many references should I check before a large first order?

Two is usually enough if one is the longest-standing customer available and both are willing to name a specific incident. If neither can, check a third.

Is it fine to accept a written testimonial instead of a call?

Treat a written testimonial as marketing material, not a reference check. It's been drafted, and you lose the ability to hear hesitation or ask a follow-up question in the moment.

What if the supplier only has customers who are all fairly new?

That's useful information on its own. It tells you how long the supplier has operated at this level of capability. It should shift you toward a smaller, closely inspected first order, not a large one.

Should I tell the reference who referred me?

Yes. It sets context, and it rarely changes what a real reference is willing to say. If a reference becomes noticeably more guarded once they know the supplier will hear about the call, that's worth noting on its own.

What is the single best question on this list if I only have time for one?

"Tell me about the last time an order from them had a problem." It's the one question a purely positive relationship can't answer. The answer tells you more than every other question combined.

Does a good reference call replace a factory audit or certification check?

No. It's one input among several, alongside documentation, samples, and capability verification. Its specific value is that it's the only one of those steps that shows you behavior under stress, not performance under observation. See our full guide to verify a supplier in India for where the reference call fits among the other steps. A reference call doesn't need to be long. Seven questions, asked to the right person, on a call instead of in writing. That's enough to learn something a certificate was never designed to tell you.

A Buyer's Reference Check Script for Industrial Suppliers

The single most useful question you can ask before a first order is one almost nobody asks. It's not "can I see your certificates." It's "can I speak to the customer you've worked with the longest."

Most buyers who do call a reference call the wrong one. They call whichever contact the supplier hands them. They ask if the supplier is good. They get told yes. They hang up having learned nothing they didn't already assume.

The seven questions below are built to avoid that outcome. Each one is designed to surface behavior, not opinion. The sections that follow explain why, and give you the follow-up questions that make the difference between a call that just confirms what you hoped, and one that actually tells you something.

Why the call gets skipped

The paperwork is what makes skipping the call feel safe. A certificate. A sample. A badge on a sourcing platform. Each one feels like a completed step. A file that looks complete reads like a decision already made. Reopening it with a phone call feels like reopening a question everyone agreed was closed.

The problem is what those documents actually prove. A certificate confirms a quality system existed on the day it was audited. A sample confirms what the shop can produce under close attention, once. Neither one tells you what the same supplier does in an ordinary bad week. A machine goes down. A material shipment is late. Your order is the smallest one on the floor that month. Only someone who has already lived through a week like that can tell you.

Call the longest customer, not the newest one

When a supplier offers you a reference, they're choosing who you talk to. A new customer is a safe reference by nature. Not enough time has passed for anything to go wrong yet. Even an engaged newer client is describing a honeymoon, not a marriage. A supplier's newest reference tells you how they behave in month one. Their oldest reference tells you how they behave in year four, after an invoice has run late at least once and the tooling has worn down at least once.

A European industrial buyer sourcing precision-turned components described exactly this pattern. The same shop offered two references. One was nine months in. One was six years in. The nine-month reference gave polished, generic praise. The six-year reference, asked the same seven questions, described a specific batch that had failed incoming inspection two years earlier. She named exactly what the supplier said when told, and how long the replacement took. That's the whole value of a reference call, in one comparison. The newer relationship had nothing to report, because nothing had happened to it yet.

Ask for the supplier's longest-standing customer by name before the call. Don't just ask for "a reference." If the supplier hesitates, offers only recent names, or says the longest-standing relationship "isn't the best point of contact," that hesitation is itself information. See the red flags section below.

The script

Ask these on a phone or video call, not by email. A written answer gets drafted and edited before you ever read it. A live answer has a pause in it, or it doesn't. That pause is data an email can never give you.

"Why did you choose this supplier over the alternative you were considering at the time?" The answer tells you what this reference actually values, so you can judge whether their standards match yours.
"Tell me about the last time an order from them had a problem, of any size." Not "have you had problems," which invites a no. Ask for the last one, specifically. Everyone has one if you've worked together long enough.
"How did you find out, and how long after it happened?" This is the question that separates a supplier who reports problems from one who waits to be caught. A reference who says "they called us before we even opened the boxes" is describing a different company than one who says "we noticed it ourselves during final assembly."
"What did they do differently after that?" A one-time mistake that produced a real process change is a different signal than a mistake that produced only an apology.
"Would you place a large first order with them again today, starting from zero?" Not "would you recommend them," which is a social question with a socially easy answer. This version forces the reference to weigh today's relationship against the risk of a brand-new one. That's exactly the decision you're making right now.
"Is there anything you check on every shipment now that you didn't check on the first one?" This surfaces the specific failure mode this particular buyer learned to watch for. That's often more useful than any general quality question.
"Is there someone else at your company, or another buyer you know, who has worked with them longer or differently than you have?" A real long-term customer will usually be able to point you somewhere. A reference who deflects this, or who is clearly the only contact the supplier has ever offered anyone, is worth noting.

How to read the answers

Specific answers are the signal, not positive ones. A reference who says "eleven days, and they upgraded our tolerance-check step afterward" has told you something you can act on. A reference who says "no real issues, they're great" after six years of orders is telling you less than it sounds like. Maybe they've had an unusually smooth run. Maybe they just aren't going to tell you about the rough one. You can't tell which from that sentence alone. Push once, gently. "Even something small?" If the answer stays vague after that, treat the reference as uninformative, not reassuring. That's not the same as a bad signal. It's just a blank one.

Listen for the pause as much as the words. A reference who answers question two instantly, in detail, is describing something they've thought about before. Usually because it mattered. A reference who goes quiet, then says "nothing comes to mind" slowly, is telling you something different than one who says the same words right away.

Red flags in the reference conversation itself

A few patterns are worth noting on their own, independent of what the reference actually says about the supplier.

The supplier offers only one reference, and resists offering a second when asked.
Every reference offered has worked with the supplier for less than a year.
The reference can't describe a single problem, of any size, across the full length of the relationship.
The reference seems to be reading from something, or gives answers that sound like marketing language rather than a description of their own experience.
You're told the longest-standing customer "isn't available" more than once, across more than one attempt.

None of these confirm a bad supplier on their own. Together, or repeated, they tell you something else. The reference check itself didn't do its job. You're back to deciding on paperwork alone.

Scorecard: what a strong reference call sounds like versus a weak one

Dimension	Strong signal	Weak signal
Choice of reference	Supplier offers their longest-standing customer without hesitation	Supplier offers only customers from the last 6-12 months
Problem disclosure	Reference describes a specific incident, unprompted after one follow-up	Reference says "no issues" and can't recall one after a follow-up
Speed of disclosure	Supplier told the customer before the customer discovered it independently	Customer discovered the problem themselves, supplier didn't proactively raise it
Response to the problem	A described process or check that changed afterward	An apology or discount, with no described change in what happens next time
Repeat-order answer	Immediate yes to placing a new large first order today	Hesitation, qualification, or an answer that shifts to praising the relationship instead of answering the question
Referral	Reference names another contact or buyer without difficulty	Reference is evasive or claims to be the only person who deals with the supplier

A supplier doesn't need a perfect column to be worth working with. Every real supplier relationship has at least one problem somewhere in its history. What the scorecard actually measures is simpler. Was the problem disclosed? Was it addressed? Did it change anything afterward? That predicts how your own first order gets handled far better than any certificate can.